Field
Various communication systems may benefit from coordination in interworking. For example, certain wireless communication systems may benefit from link setup level coordination, such as coordination between a first radio access technology base station and a terminal that is setting up a link to a second radio access technology.
Description of the Related Art
Data offloading may provide an enhancement by increasing the throughput of radio systems. In data offloading, a terminal may have database containing the network operating and security parameters. Networks can be listed in a prioritized order from the most preferred to the least preferred. In particular, the cellular network operators may want to offload traffic from their cellular networks to their own or their roaming partners' Wi-Fi hotspots, and vice versa from the Wi-Fi hotspots to the cellular network.
A device can use the network identifiers and security parameters to take a local access point (AP) of a wireless access network (WLAN) into use. The information of the database may be infrequently updated. Thus, availability of the network, network congestion and device link failures may affect the service offered to the user of the device.
Link creation to the WLAN network may have many steps and phases. Typically a WLAN network may be discovered first. In network discovery, the WLAN device can receive a frame transmitted to or from the AP. Typically the network discovery is done when the beacon, measurement pilot, fast initial link setup discovery (FILS), or probe response frame from the AP is received. Typically, during the discovery process, the link performance to the AP is assessed and the congestion level of the AP and the capabilities of the AP are detected. In discovery operation, the terminal conventionally authenticates the AP or ensures that AP operates correctly.
After discovery, the terminal conventionally creates 0-authentication. In 0-authentication, the terminal may implement a simple authentication mechanism. After 0-authentication the terminal can associate with the AP.
In the associated state, the AP conventionally performs 802.1X protocol and provides Robust Security Network Authentication (RSNA) with the 4-way handshake and the group key handshake, and then opens an 802.1x port to the internet. The RSNA operation typically consists of transmission of 10-30 authentication frames. Depending on the network congestion, authentication server implementation and its parameters, and depending on the authentication server congestion, the duration of the RSNA signaling may vary.
After RSNA authentication, the terminal executes the Dynamic Host Configuration Protocol (DHCP) Request or by other means gets IP addresses for its operation in the internet. By having a valid IP address and authentication keys the terminal ensures that it may transmit traffic or may start to transmit traffic to the internet, or it may receive traffic from the Internet.
Hotspot 2.0 protocol has defined a mechanism in which the terminal may perform low weight authentication during the discovery phase. The target of this operation is to ensure that discovery information is received from the correct AP.
Similarly, fast initial link setup (802.11ai) relates to the reduction of the link setup time. In particularly, 802.11ai attempts to reduce the time required for network discovery and authentication. In general, the WLAN link setup phases are defined in IEEE 802.11-2012 or in IEEE 802.11ai, for example in IEEE 802.11ai D0.6, each of which is hereby incorporated herein by reference in its entirety.